The present invention is directed to novel diaminothiazoles of formula 
These compounds inhibit cyclin-dependent kinase 4 (Cdk4) and are selective against Cdk2 and Cdk1. These compounds and their pharmaceutically acceptable salts and esters have antiproliferative activity and are useful in the treatment or control of cancer, in particular solid tumors. This invention is also directed to pharmaceutical compositions containing such compounds and to methods of treating or controlling cancer, most particularly the treatment or control of breast, lung and colon and prostate tumors. Finally, this invention is also directed to novel intermediate compounds useful in the preparation of a compound of formula I.
Uncontrolled cell proliferation is the hallmark of cancer. Cancerous tumor cells typically have some form of damage to the genes that directly or indirectly regulate the cell-division cycle.
The progression of cells through the various phases of the cell cycle is regulated by a series of multienzyme complexes consisting of a regulatory protein, a cyclin, and a kinase. These kinases are called cyclin-dependent kinases (Cdks). The Cdks are expressed throughout the cell cycle, while the levels of the cyclins vary depending on the stage of the cell cycle.
The transition from G1 phase into S phase is regulated by the complex of Cdk4 with cyclin D. This complex phosphorylates the tumor supressor protein Retinoblastoma (pRb), releasing the transcription factor E2F and allowing the expression of genes required in S phase (Nevins, J. R. Science 1992, 258, 424-429). Blocking the activity of the Cdk4/cyclin D complex arrests the cell cycle in G1 phase. For example, the proteins of the INK4 family, including p16INK4a, which block the kinase activity of the Cdk4/cyclin D complex, cause arrest in G1 (Sherr, C. J. Science 1996, 274, 1672-1677).
Recent experiments show that the complex of Cdk4 with cyclin D3 also plays a role in cell cycle progression through G2 phase. Inhibition of this complex, either by p16 or using a dominant negative Cdk4, results in arrest in G2 phase in cells that do not express pRb (Gabrielli B. G. et al. J. Biol. Chem. 1999, 274, 13961-13969).
Numerous defects in the pRb pathway have been shown to be involved in various cancers. For example, overexpression of Cdk4 has been observed in cases of hereditary melanoma (Webster, K. R. Exp. Opin. Invest. Drugs 1998, 7, 865-887); cyclin D is overexpressed in many human cancers (Sherr, C. J. Science 1996, 274, 1672-1677); p16 is mutated or deleted in many tumors (Webster, K. R. Exp. Opin. Invest Drugs 1998, 7, 865-887); and pRb function is lost through mutation or deletion in many human cancers (Weinberg, R. A. Cell 1995, 81, 323-330). Defects in this pathway have also been shown to have an effect on prognosis. For example, loss of p16 is correlated with poor prognosis in non-small-cell lung carcinoma (NSCLC) and malignant melanoma (Tsihlias, J. et al. Annu. Rev. Med. 1999, 50, 401-423).
Because of the involvement of the Cdk4/cyclin D/pRb pathway in human cancer through its role in regulating progression of the cell cycle from G1 to S phase, and the potential therapeutic benefit from modulating this pathway, there has been considerable interest in agents that inhibit or promote elements of this pathway. For example, effects on cancer cells have been shown using antibodies, antisense oligonucleotides and overexpression or addition of proteins involved in the pathway. See, e.g., Lukas, J. et al. Nature 1995, 79, 573-582; Nevins, J. R. Science 1992, 258, 424-429; Lim, I. K. et al. Molecular Carcinogenesis 1998, 23, 25-35; Tam, S. W. et al. Oncogene 1994, 9, 2663-2674; Driscoll, B. et al. Am. J. Physiol. 1997, 273 (Lung Cell. Mol. Physiol.), L941-L949; and Sang, J. et al. Chin. Sci. Bull. 1999, 44, 541-544). There is thus an extensive body of literature validating the use of compounds inhibiting targets in the Cdk4 pathway as anti-proliferative therapeutic agents.
It is thus desirable to identify chemical inhibitors of Cdk4 kinase activity. It is particularly desirable to identify small molecule compounds that may be readily synthesized and are effective in inhibiting Cdk4 or Cdk4/cyclin complexes, for treating one or more types of tumors.
There are several examples of small molecule inhibitors of the cyclin-dependent kinases, including Cdk4 (Rosania, G. R. et al. Exp. Opin. Ther. Patents 2000, 10, 215-230). Several of these compounds inhibit multiple targets.
For example, Flavopiridol (Aventis) 
is in Phase II clinical trials for lymphoma and multiple myeloma and also for the treatment of solid tumors. It inhibits Cdk1, Cdk2 and Cdk4 and it blocks cells in both G1 and G2 phases. It is also a weaker inhibitor of PKC and EGFR (Senderowicz, A. M. et al. J. Natl. Cancer Inst 2000, 92, 376-387).
WO9716447 (Mitotix) discloses the following compounds related to flavopiridol 
Some of these compounds are stated to inhibit Cdk4.
WO9943675 and WO9943676 (Hoechst) disclose the following purine derivatives 
which are stated to inhibit Cdk2 and Cdk4.
WO9833798 (Warner-Lambert) discloses the following pyridopyrimidines 
These compounds are stated to inhibit the cyclin dependent kinases Cdk1, Cdk2, and Cdk4. Some of these compounds also inhibit the receptor tyrosine kinases PDGFR and EGFR, and the cellular Src protein kinase, c-Src.
WO9909030 (Warner-Lambert) discloses naphthyridinones 
that inhibit PDGFR, FGFR, c-Src, and the cyclin dependent kinases Cdk1, Cdk2, and Cdk4.
WO0039101 (AstraZeneca) discloses diaminopyrimidines 
that inhibit Cdk4 and FAK3.
WO0012485 (Zeneca) discloses diaminopyrimidines 
that inhibit Cdk4 and FAK3.
WO9924416 (Bristol-Myers Squibb) discloses aminothiazole inhibitors of formula 
The compounds inhibit Cdk1, Cdk2 and Cdk4.
WO9921845 (Agouron) discloses diaminothiazole inhibitors of Cdk1, Cdk2 and Cdk4, having the following structure 
where R1 and R2 are ring systems. This patent application indicates that in cases where the R2 ring system does not bear an ortho substituent, the compounds lack potency and selectivity as inhibitors of Cdk4.
Finally, WO0075120 (Agouron) discloses diaminothiazole inhibitors of protein kinases including VEGF-R, FGF-R, CDK complexes, TEK, CHK1, LCK, and FAK, having the following structure 
It is desirable to provide small molecule inhibitors of Cdk4 that are selective against other Cdks. That is, the small molecule is significantly more inhibitory (at least 10 times, preferably 100 times) of Cdk4 than Cdk1 and Cdk2. This parameter is desirable because of the potential concomitant toxicity and other undesirable complications that may follow from inhibiting multiple targets. Thus, for purposes of this invention, the inhibition of Cdk2 and Cdk1 are monitored to determine the selectivity of the inhibition of Cdk4. A compound that exhibits selectivity against Cdk2 and Cdk1 is expected to have a better safety profile than a compound that is not selective between Cdk4, Cdk2 and Cdk1.
There continues to be a need for easily synthesized, small molecule compounds that are specific inhibitors of Cdk4 for the treatment or control of one or more types of solid tumors. It is an object of this invention to provide such compounds, compositions containing such compounds, and methods of using such compounds in the treatment or control of breast, colon, lung and prostate tumors.
The present invention is directed to novel diaminothiazoles capable of selectively inhibiting the activity of Cdk4. These compounds are useful in the treatment or control of cancer, in particular the treatment or control of solid tumors. In particular this invention is directed to a compound of formula 
or the pharmaceutically acceptable salts or esters thereof, wherein
R1 is selected from the group consisting of
H,
lower alkyl that optionally may be substituted with a group selected from OR6, cycloalkyl, and NR7R8,
cycloalkyl,
COR9, and
SO2R10;
R2 is selected from the group consisting of
H,
F,
Cl, and
CH3;
R3, R4 and R5 are each independently selected from the group consisting of
H,
lower alkyl, which optionally may be substituted with a group selected from OR6 and NR7R8,
OR11,
NR12R13,
halogen,
NO2,
CONR6R9,
NHSO2R14,
CN,
S-lower alkyl,
OCF3, and
OCHF2,
or alternatively, R3 and R4 taken together with the two carbons and the bond between them from the benzene ring (D) to which R3 and R4 are attached can form a ring system having up to two additional rings, each of said rings
having 5-7 atoms, and the ring attached to the benzene ring (D) optionally including one or more hetero atoms and being optionally substituted by lower alkyl,
provided that R3 and R4 are not simultaneously xe2x80x94OCH3, and provided further that R4 is not xe2x80x94Cl when R3 is xe2x80x94NO2;
R6 and R9 are independently selected from the group consisting of
H, and
lower alkyl that optionally may be substituted by OH and halogen;
R7 and R8 are independently selected from the group consisting of
H, and
lower alkyl that optionally may be substituted by OR6,
or, alternatively, R7 is H and R8 is OH,
or, alternatively, NR7R8 can optionally form a ring having 5-6 atoms, said ring optionally including one or more additional hetero atoms and being optionally substituted by the group consisting of one or more of OR6 and lower alkyl which itself may be optionally substituted by OH;
R10 is selected from the group consisting of
lower alkyl which optionally may be substituted by one or more chlorine or fluorine, and
NH2;
R11 is selected from the group consisting of
H, and
lower alkyl that optionally may be substituted by OR6, COOH, halogen and NR15R16;
R12 and R13 are independently selected from the group consisting of
H,
lower alkyl that optionally may be substituted with a group selected from OR6, COOH and NR15R16,
COR17, and
SO2R18,
provided that only one of R12 and R13 is COR17 or SO2R18,
or alternatively NR12R13 can optionally form a ring having 5-6 atoms, said ring optionally including one or more additional hetero atoms and being optionally substituted by the group consisting of one or more of OR6 and lower alkyl which itself may be optionally substituted by OH;
R14 is lower alkyl;
R15 and R16 are independently selected from the group consisting of
H, and
lower alkyl that optionally may be substituted by OH,
or alternatively NR15R16 can optionally form a ring having 5-6 atoms, said ring optionally including one or more additional hetero atoms and being optionally substituted by the group consisting of one or more of OR6 and lower alkyl which itself may be optionally substituted by OH;
R17 is selected from the group consisting of
H, and
lower alkyl which optionally may be substituted by OH, COOH and NR15R16; and
R18 is lower alkyl.
The present invention is also directed to pharmaceutical compositions comprising a therapeutically effective amount of one or more compounds of formula I and a pharmaceutically acceptable carrier or excipient.
The present invention is further directed to a method for treating solid tumor, in particular breast or colon tumors, by administering to a human patient in need of such therapy an effective amount of a compound of formula I, its salt and/or ester.
The present invention is also directed to novel intermediate compounds useful in the preparation of compounds of formula I.
Definitions
As used herein, the following terms shall have the following definitions.
xe2x80x9cCycloalkylxe2x80x9d means a non-aromatic, partially or completely saturated cyclic aliphatic hydrocarbon group containing 3 to 8 atoms. Examples of cycloalkyl groups include cyclopropyl, cyclopentyl and cyclohexyl.
xe2x80x9cEffective amountxe2x80x9d means an amount that is effective to prevent, alleviate or ameliorate symptoms of disease or prolong the survival of the subject being treated.
xe2x80x9cHalogenxe2x80x9d means fluorine, chlorine, bromine or iodine.
xe2x80x9cHetero atomxe2x80x9d means an atom selected from N, O and S.
xe2x80x9cIC50xe2x80x9d refers to the concentration of a particular compound according to the invention required to inhibit 50% of a specific measured activity. IC50 can be measured, inter alia, as is described in Example 125, infra.
xe2x80x9cLower alkylxe2x80x9d denotes a straight-chain or branched saturated aliphatic hydrocarbon having 1 to 6, preferably 1 to 4, carbon atoms. Typical lower alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, t-butyl, 2-butyl, pentyl, hexyl and the like.
xe2x80x9cPharmaceutically acceptable esterxe2x80x9d refers to a conventionally esterified compound of formula I having a carboxyl group, which esters retain the biological effectiveness and properties of the compounds of formula I and are cleaved in vivo (in the organism) to the corresponding active carboxylic acid. Examples of ester groups which are cleaved (in this case hydrolyzed) in vivo to the corresponding carboxylic acids (R24C(xe2x95x90O)OH) are lower alkyl esters which may be substituted with NR25R26 where R25 and R26 are lower alkyl, or where NR25R26 taken together form a monocyclic aliphatic heterocycle, such as pyrrolidine, piperidine, morpholine, N-methylpiperazine, etc.; acyloxyalkyl esters of the formula R24C(xe2x95x90O)OCHR27OC(xe2x95x90O)R28 where R27 is hydrogen or methyl, and R28 is lower alkyl or cycloalkyl; carbonate esters of the formula R24C(xe2x95x90O)OCHR27OC(xe2x95x90O)OR29 where R27 is hydrogen or methyl, and R29 is lower alkyl or cycloalkyl; or aminocarbonylmethyl esters of the formula R24C(xe2x95x90O)OCH2C(xe2x95x90O)NR25R26 where R25 and R26 are hydrogen or lower alkyl, or where NR25R26 taken together form a monocyclic aliphatic heterocycle, such as pyrrolidine, piperidine, morpholine, N-methylpiperazine, etc.
Examples of lower alkyl esters are the methyl, ethyl, and n-propyl esters, and the like. Examples of lower alkyl esters substituted with NR19R20 are the diethylaminoethyl, 2-(4-morpholinyl)ethyl, 2-(4-methylpiperazin-1-yl)ethyl esters, and the like. Examples of acyloxyalkyl esters are the pivaloxymethyl, 1-acetoxyethyl, and acetoxymethyl esters. Examples of carbonate esters are the 1-(ethoxycarbonyloxy)ethyl and 1-(cyclohexyloxycarbonyloxy)ethyl esters. Examples of aminocarbonylmethyl esters are the N,N-dimethylcarbamoylmethyl and carbamoylmethyl esters.
Further information concerning examples of and the use of esters for the delivery of pharmaceutical compounds is available in Design of Prodrugs. Bundgaard H ed. (Elsevier, 1985). See also, H. Ansel et. al., Pharmaceutical Dosage Forms and Drug Delivery Systems (6th Ed. 1995) at pp. 108-109; Krogsgaard-Larsen, et. al., Textbook of Drug Design and Development (2d Ed. 1996) at pp. 152-191.
xe2x80x9cPharmaceutically acceptable saltxe2x80x9d refers to conventional acid-addition salts or base-addition salts that retain the biological effectiveness and properties of the compounds of formula I and are formed from suitable non-toxic organic or inorganic acids or organic or inorganic bases. Sample acid-addition salts include those derived from inorganic acids such as hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, sulfamic acid, phosphoric acid and nitric acid, and those derived from organic acids such as p-toluenesulfonic acid, salicylic acid, methanesulfonic acid, oxalic acid, succinic acid, citric acid, malic acid, lactic acid, fumaric acid, and the like. Sample base-addition salts include those derived from ammonium, potassium, sodium and, quaternary ammonium hydroxides, such as for example, tetramethylammonium hydroxide. The chemical modification of a pharmaceutical compound (i.e. drug) into a salt is a technique well known to pharmaceutical chemists to obtain improved physical and chemical stability, hygroscopicity, flowability and solubility of compounds. See, e.g., H. Ansel et. al., Pharmaceutical Dosage Forms and Drug Delivery Systems (6th Ed. 1995) at pp. 196 and 1456-1457.
xe2x80x9cPharmaceutically acceptable,xe2x80x9d such as pharmaceutically acceptable carrier, excipient, etc., means pharmacologically acceptable and substantially non-toxic to the subject to which the particular compound is administered.
xe2x80x9cSubstituted,xe2x80x9d as in substituted alkyl, means that the substitution can occur at one or more positions and, unless otherwise indicated, that the substituents at each substitution site are independently selected from the specified options.
xe2x80x9cTherapeutically effective amountxe2x80x9d means an amount of at least one compound of Formula I, or a pharmaceutically acceptable salt or ester thereof, that significantly inhibits proliferation and/or prevents differentiation of a human tumor cell, including human tumor cell lines.
In one embodiment, the invention is directed to a compound of formula 
or the pharmaceutically acceptable salts or esters thereof, wherein
R1 is selected from the group consisting of
H,
lower alkyl that optionally may be substituted from the group selected from OR6, cycloalkyl, and NR7R8,
cycloalkyl,
COR9, and
SO2R10;
R2 is selected from the group consisting of
H,
F,
Cl, and
CH3;
R3, R4 and R5 are each independently selected from the group consisting of
H,
lower alkyl, which optionally may be substituted with a group selected from OR6 and NR7R8,
OR11,
NR12R13,
halogen,
NO2,
CONR6R9,
NHSO2R14,
CN,
S-lower alkyl,
OCF3, and
OCHF2,
or alternatively, R3 and R4 taken together with the two carbons and the bond between them from the benzene ring (D) to which R3 and R4 are attached can form a ring system having up to two additional rings, each of said rings having 5-7 atoms, and the ring attached to the benzene ring (D) optionally including one or more hetero atoms and being optionally substituted by lower alkyl,
provided that R3 and R4 are not simultaneously xe2x80x94OCH3, and provided further that R4 is not xe2x80x94Cl when R3 is xe2x80x94NO2;
R6 and R9 are independently selected from the group consisting of
H, and
lower alkyl that optionally may be substituted by OH and halogen;
R7 and R8 are independently selected from the group consisting of
H, and
lower alkyl that optionally may be substituted by OR6,
or, alternatively, R7 is H and R8 is OH,
or, alternatively, NR7R8 can optionally form a ring having 5-6 atoms, said ring optionally including one or more additional hetero atoms and being optionally substituted by the group consisting of one or more of OR6 and lower alkyl which itself may be optionally substituted by OH;
R10 is selected from the group consisting of
lower alkyl which optionally may be substituted by one or more chlorine or fluorine, and
NH2;
R11 is selected from the group consisting of
H, and
lower alkyl that optionally may be substituted by a group selected from OR6, COOH, halogen and NR15R16;
R12 and R13 are independently selected from the group consisting of
H,
lower alkyl that optionally may be substituted with a group selected from OR6, COOH and NR15R16,
COR17, and
SO2R18,
provided that only one of R12 and R13 is COR17 or SO2R18,
or alternatively NR12R13 can optionally form a ring having 5-6 atoms, said ring optionally including one or more additional hetero atoms and being optionally substituted by the group consisting of one or more of OR6 and lower alkyl which itself may be optionally substituted by OH;
R14 is lower alkyl;
R15 and R16 are independently selected from the group consisting of
H, and
lower alkyl that optionally may be substituted by OH,
or alternatively NR15R16 can optionally form a ring having 5-6 atoms, said ring optionally including one or more additional hetero atoms and being optionally substituted by the group consisting of one or more of OR6 and lower alkyl which itself may be optionally substituted by OH;
R17 is selected from the group consisting of
H, and
lower alkyl which optionally may be substituted by OH, COOH and NR15R16; and
R18 is lower alkyl.
In a preferred embodiment of the compounds of formula I, R1 is selected from the group consisting of H, CH2CH2OH, CH2CH2CH2OH, CH3COxe2x80x94, CH(CH3)2, CH2CH(CH3)2, cyclopropylmethyl and CH3. More preferably, R1 is H, methyl, CH2CH2CH2OH, or CH(CH3)2.
In another preferred embodiment of the compounds of formula I, R2 is selected from the group consisting of H and fluorine, most preferably H.
In another preferred embodiment of the compounds of formula I, R3 is selected from the group OR11, lower alkyl, NH2, Cl, F, H, , OCHF2, and NO2. More preferably, R3 is OCH3, F, lower alkyl or OCHF2. Most preferably, R3 is F, OCH3 or CH2CH3.
In another preferred embodiment of the compounds of formula I, R4 is selected from the group consisting of acetamido, chloro, diethylamino, hydrogen, hydroxy, hydroxyethylamino, [1-(hydroxymethyl)-3-methylbutyl]amino, 1-(3-hydroxymethyl)piperidinyl, 4-hydroxy-1-piperidinyl, methoxy, 2-methoxy-ethylamino, 2-methyl-1-pyrrolidinyl, morpholino, piperidinyl, pyrrolidinyl. More preferably, R4 is selected from the group consisting of H and CH3Oxe2x80x94.
When R3 and R4 taken together with the benzene ring to which they are attached form a ring system, preferred ring systems are 2-dibenzofuranyl, 1,3-benzodioxol-5-yl, 2,3-dihydro-1,4-benzodioxin-6-yl, or 3,4-dihydro-2H-1,5-benzodioxepin-7-yl, more preferably 2,3-dihydro-1,4-benzodioxin-6-yl.
In another preferred embodiment of the compounds of formula I, R5 is selected from the group consisting of H, OR11 and F, most preferably H.
In another preferred embodiment of the compounds of formula I,
R1 is selected from the group consisting of
H, and
lower alkyl that optionally may be substituted by OR6;
R2 is selected from the group consisting of H and F;
R3 is selected from the group consisting of
H,
lower alkyl
halogen,
NR12R13 
NO2,
OCHF2, and
OR11;
R4 is selected from the group consisting of
H,
lower alkyl that optionally may be may be substituted by OR6,
halogen, and
NR12R13,
or alternatively, R3 and R4 taken together with the two carbons and the bond between them from the benzene ring (D) to which R3 and R4 are attached can form a ring system having up to two additional rings, each of said rings having 5-7 atoms, and the ring attached to the benzene ring (D) optionally including one or more hetero atoms and being optionally substituted by lower alkyl,
provided that R4 is not xe2x80x94Cl when R3 is xe2x80x94NO2;
R6 is selected from the group consisting of
H, and
methyl;
R11 is selected from the group consisting of
H, and
lower alkyl that optionally may be substituted by a group selected from OR6, COOH, halogen and NR15R16;
R12 and R13 are independently selected from the group consisting of
H,
lower alkyl that optionally may be substituted with a group selected from OR6, COOH and NR15R16,
or alternatively NR12R13 can optionally form a ring having 5-6 atoms, said ring optionally including one or more additional hetero atoms and being optionally substituted by the group consisting of one or more of OR6 and lower alkyl which itself may be optionally substituted by OH; and
R15 and R16 are independently selected from the group consisting of
H, and
lower alkyl that optionally may be substituted by OH,
or alternatively NR15R16 can optionally form a ring having 5-6 atoms, said ring optionally including one or more additional hetero atoms and being optionally substituted by the group consisting of one or more of OR6 and lower alkyl which itself may be optionally substituted by OH.
In a most preferred embodiment of the compounds of formula I,
R1 is selected from the group consisting of
H,
CH2CH2OH,
CH2CH2CH2OH,
CH3COxe2x80x94,
CH(CH3)2,
CH2CH(CH3)2,
cyclopropylmethyl, and
CH3;
R2 is selected from the group consisting of
H and F;
R3 is selected from the group consisting of
OR11,
lower alkyl,
NH2,
Cl,
F,
H,
OCHF2, and
NO2;
R4 is selected from the group consisting of
H, and
diethylamino;
R5 is H; and
R11 is unsubstituted lower alkyl.
In another most preferred embodiment of the compounds of formula I,
R1 is selected from the group consisting of
H,
CH2CH2CH2OH,
CH(CH3)2,
CH3, and
cyclopropylmethyl;
R2, R4 and R5 are H; and
R3 is selected from the group consisting of
OCH3,
F, and
CH2CH3.
The following are examples of preferred compounds of formula I:
[4-Amino-2-[[4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl](2,3-dihydro-1,4-benzodioxin-6-yl)methanone (Example 24),
[4-Amino-2-[[4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl](1,3-benzodioxol-5-yl)methanone (Example 25),
[4-Amino-2-[[4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl][4-(1-pyrrolidinyl)phenyl]methanone (Example 26),
[4-Amino-2-[[4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl][4-(1-piperidinyl)phenyl]methanone (Example 27),
[4-Amino-2-[[4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl][4-(4-morpholinyl)phenyl]methanone, acetate salt (Example 28),
[4-Amino-2-[[4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl](3,4-dihydro-2H-1,5-benzodioxepin-7-yl)methanone (Example 29),
[4-Amino-2-[[4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl]-(4-hydroxyphenyl)methanone (Example 30),
[4-Amino-2-[[4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl](3-nitrophenyl)methanone (Example 31),
[4-Amino-2-[[4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl](4-methoxyphenyl)methanone (Example 32),
[4-Amino-2-[[4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl][4-(diethylamino)phenyl]methanone (Example 33),
[4-Amino-2-[[4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl](2-dibenzofuranyl)methanone (Example 34),
[4-Amino-2-[[4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl](3-fluoro-4-methoxyphenyl)methanone (Example 35),
[4-Amino-2-[[4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl](3-methoxyphenyl)methanone (Example 36),
[4-Amino-2-[[4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl](3,4-dichlorophenyl)methanone (Example 37),
[4-Amino-2-[[3-fluoro-4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl](1,3-benzodioxol-5-yl)methanone (Example 38),
[4-Amino-2-[[3-fluoro-4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl](3,5-dimethoxyphenyl)methanone (Example 39),
[4-Amino-2-[[3-fluoro-4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl](3-methoxyphenyl)methanone (Example 40),
[4-Amino-2-[[4-[4-(1-methylethyl)-1-piperazinyl]phenyl]amino]-5-thiazolyl](2,3-dihydro-1,4-benzodioxin-6-yl)methanone (Example 41),
[4-Amino-2-[[4-[4-(1-methylethyl)-1-piperazinyl]phenyl]amino]-5-thiazolyl](1,3-benzodioxol-5-yl)methanone (Example 42),
[4-Amino-2-[[4-[4-(1-methylethyl)-1-piperazinyl]phenyl]amino]-5-thiazolyl](3-methoxyphenyl)methanone (Example 43),
[4-Amino-2-[[4-[4-(1-methylethyl)-1-piperazinyl]phenyl]amino]-5-thiazolyl](3,5-dimethoxyphenyl)methanone (Example 44),
N-[4-[[4-Amino-2-[[4-[4-(1-methylethyl)-1-piperazinyl]phenyl]amino]-5-thiazolyl]carbonyl]phenyl]acetamide (Example 45),
[4-Amino-2-[[4-[4-(1-methylethyl)-1-piperazinyl]phenyl]amino]-5-thiazolyl][4-(diethylamino)phenyl]methanone (Example 46),
1-Acetyl-4-[4-[[4-amino-5-[(1,3-benzodioxol-5-yl)carbonyl]-2-thiazolyl]amino]phenyl]piperazine (Example 47),
1-Acetyl-4-[4-[[4-amino-5-[4-(diethylamino)benzoyl]-2-thiazolyl]amino]phenyl]piperazine, trifluoroacetate salt (Example 48),
[4-Amino-2-[[4-[4-(2-hydroxyethyl)-1-piperazinyl]phenyl]amino]-5-thyiazolyl](2,3-dihydro-1,4-benzodioxin-6-yl)methanone (Example 49),
[4-Amino-2-[[4-[4-(2-hydroxyethyl)-1-piperazinyl]phenyl]amino]-5-thiazolyl][4-(1-pyrrolidinyl)phenyl]methanone (Example 50),
[4-Amino-2-[[4-[4-(2-hydroxyethyl)-1-piperazinyl]phenyl]amino]-5-thiazolyl](3-fluorophenyl)methanone (Example 51),
[4-Amino-2-[[4-[4-(2-hydroxyethyl)-1-piperazinyl]phenyl]amino]-5-thiazolyl](3,5-difluorophenyl)methanone (Example 52),
[4-Amino-2-[[4-[4-(2-hydroxyethyl)-1-piperazinyl]phenyl]amino]-5-thiazolyl](3-methoxyphenyl)methanone (Example 53),
[4-Amino-2-[[4-(1-piperazinyl)phenyl]amino]-5-thiazolyl](3-fluorophenyl)methanone (Example 54),
[4-Amino-2-[[4-(1-piperazinyl)phenyl]amino)-5-thiazolyl][4-(1-pyrrolidinyl)phenyl]methanone (Example 55),
[4-Amino-2-[[4-(1-piperazinyl)phenyl]amino)-5-thiazolyl](3-fluoro-4-methoxyphenyl)methanone (Example 56),
[4-Amino-2-[[4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl][4-(2-hydroxyethyl)amino-3-nitrophenyl]methanone (Example 57),
[4-Amino-2-[[4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl][3-nitro-4-(1-pyrrolidinyl)phenyl]methanone (Example 58),
[4-Amino-2-[[4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl)[3-nitro-4-(4-morpholinyl)phenyl]methanone (Example 59),
[4-Amino-2-[[4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl][3-nitro-4-[(2-methoxyethyl)amino]phenyl]methanone (Example 60),
racemic [4-Amino-2-[[4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl][3-nitro-4-[3-(hydroxymethyl)-1-piperidinyl]phenyl]methanone (Example 61),
racemic [4-Amino-2-[[4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl][3-nitro-4-(2-methyl-1-pyrrolidinyl)phenyl]methanone (Example 62),
(R)-[4-Amino-2-[[4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl][3-nitro-4-[[1-(hydroxymethyl)-3-methylbutyl]amino]phenyl]methanone (Example 63),
[4-Amino-2-[[4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl][3-nitro-4-(4-hydroxy-1-piperidinyl)phenyl]methanone (Example 64),
[4-Amino-2-[[4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl][3-amino-4-(4-pyrrolidinyl)phenyl]methanone (Example 65),
(R)-[3-Amino-4-[[1-(hydroxymethyl)-3-methylbutyl]amino]phenyl][4-amino-2-[[4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl]methanone (Example 66),
[4-Amino-2-[[3-fluoro-4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl] (2,3-dihydro-1,4-benzodioxin-5-yl)methanone (Example 67),
[4-Amino-2-[[3-fluoro-4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl] [4-(1-pyrrolidinyl)phenyl]methanone (Example 68),
{4-Amino-2-[4-(4-isopropyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(3-methoxy-phenyl)-methanone, phosphoric acid (Example 69),
{4-Amino-2-[4-(4-methyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}(3methylsulfanyl-phenyl)-methanone (Example 70).
(4-Amino-2-{4-[4-(3-hydroxy-propyl)-piperazin-1-yl]-phenylamino}-thiazol-5-yl)-(3-fluoro-phenyl)-methanone (Example 71),
(4-Amino-2-{4-[4-(3-hydroxy-propyl)-piperazin-1-yl]-phenylamino}-thiazol-5-yl)-(3-methoxy-phenyl)-methanone (Example 72),
3-(4-Amino-2-{4-[4-(3-hydroxy-propyl)-piperazin-1-yl]-phenylamino}-thiazole-5-carbonyl)-benzonitrile (Example 73),
(4-Amino-2-{4-[4-(3-hydroxy-propyl)-piperazin-1-yl]-phenylamino}-thiazol-5-yl)-(3-nitro-phenyl)-methanone (Example 74),
(4-Amino-2-{4-[4-(3-hydroxy-propyl)-piperazin-1-yl]-phenylamino}-thiazol-5-yl)-m-tolyl-methanone (Example 75),
(4-Amino-2-{4-[4-(3-hydroxy-propyl)-piperazin-1-yl]-phenylamino}-thiazol-5-yl)-(3-ethyl-phenyl)-methanone (Example 76),
{4-Amino-2-[4-(4-methyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(3-ethyl-phenyl)-methanone (Example 77),
{4-Amino-2-[4-(4-methyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-m-tolyl-methanone (Example 78),
3-{4-Amino-2-[4-(4-isopropyl-piperazin-1-yl)-phenylamino]-thiazole-5-carbonyl}-benzonitrile (Example 79).
{4-Amino-2-[4-(4-isopropyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(3-fluoro-phenyl)-methanone, with hydrogen bromide (Example 80),
{4-Amino-2-[4-(4-isopropyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(3,4,5-trifluoro-phenyl)-methanone, with hydrogen bromide (Example 81),
{4-Amino-2-[4-(4-isopropyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(3,5-difluoro-phenyl)-methanone, with hydrogen bromide (Example 82),
4-Amino-2-{4-[4-(2-methoxy-ethyl)-piperazin-1-yl]-phenylamino}-thiazol-5-yl)-(3-fluoro-4-methoxy-phenyl)-methanone, hydrogen bromide (Example 83),
{4-Amino-2-[4-(4-isopropyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(4-fluoro-3-methoxy-phenyl)-methanone, with hydrogen bromide (Example 84),
{4-Amino-2-[4-(4-isopropyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(3-fluoro-4-methoxy-phenyl)-methanone, with hydrogen bromide (Example 85),
{4-Amino-2-[4-(4-isopropyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(4-difluoromethoxy-phenyl)-methanone, with hydrogen bromide (Example 86),
{4-Amino-2-[4-(4-isopropyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(3-trifluoromethoxy-phenyl)-methanone, with hydrogen bromide (Example 87),
{4-Amino-2-[4-(4-isopropyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(4-piperidin-1-yl-phenyl)-methanone, with hydrogen bromide (Example 88),
{4-Amino-2-[4-(4-isopropyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(4-morpholin-4-yl-phenyl)-methanone, with hydrogen bromide (Example 89),
(4-Amino-2-{4-[4-(2-methoxy-ethyl)-piperazin-1-yl]-phenylamino}-thiazol-5-yl)-(3,5-difluoro-phenyl)-methanone, with hydrogen bromide (Example 90),
(4-Amino-2-{4-[4-(2-methoxy-ethyl)-piperazin-1-yl]-phenylamino}-thiazol-5-yl)-(3,4-difluoro-phenyl)-methanone, with hydrogen bromide (Example 91),
(4-Amino-2-{4-[4-(2-methoxy-ethyl)-piperazin-1-yl]-phenylamino}-thiazol-5-yl)-(3-methoxy-phenyl)-methanone, with hydrogen bromide (Example 92),
(4-Amino-2-{4-[4-(2-methoxy-ethyl)-piperazin-1-yl]-phenylamino}-thiazol-5-yl)-benzo[1,3]dioxol-5-yl-methanone, with hydrogen bromide (Example 93),
4-Amino-2-{4-[4-(2-methoxy-ethyl)-piperazin-1-yl]-phenylamino}-thiazol-5-yl)-(2,3-dihydro-benzo[1,4]dioxin-6-yl)-methanone, with hydrogen bromide (Example 94),
{4-Amino-2-[4-(4-methyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(3,5-difluoro-phenyl)-methanone, with hydrogen bromide (Example 95),
{4-Amino-2-[4-(4-methyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(3,5-difluoro-4-methoxy-phenyl)-methanone, with hydrogen bromide (Example 96),
{4-Amino-2-[4-(4-methyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(4-fluoro-3-methoxy-phenyl)-methanone, with hydrogen bromide(Example 97),
{4-Amino-2-[4-(4-methyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(3-trifluoromethoxy-phenyl)-methanone, with hydrogen bromide (Example 98),
(4-Amino-2-{4-[4-(2-hydroxy-ethyl)-piperazin-1-yl]-phenylamino}-thiazol-5-yl)-(3-fluoro-phenyl)-methanone, with acetic acid (Example 99),
[4-Amino-2-(4-piperazin-1-yl-phenylamino)-thiazol-5-yl]-(3,4,5-trifluoro-phenyl)-methanone, with acetic acid (Example 100),
[4-Amino-2-(4-piperazin-1-yl-phenylamino)-thiazol-5-yl]-(3,5-difluoro-4-methoxy-phenyl)-methanone, with acetic acid (Example 101),
[4-Amino-2-(4-piperazin-1-yl-phenylamino)-thiazol-5-yl]-(4-fluoro-3-methoxy-phenyl)-methanone, with acetic acid (Example 102),
[4-Amino-2-(4-piperazin-1-yl-phenylamino)-thiazol-5-yl]-(3-trifluoromethoxy-phenyl)-methanone, with acetic acid (Example 103),
{4-Amino-2-[4-(4-sec-butyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(3-fluoro-phenyl)-methanone (Example 104),
{4-Amino-2-[4-(4-sec-butyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-benzo[1,3]dioxol-5-yl-methanone (Example 105),
{4-Amino-2-[4-(4-sec-butyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(2,3-dihydro-benzo[1,4]dioxin-6-yl)-methanone (Example 106),
{4-Amino-2-[4-(4-cyclopentyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-benzo[1,3]dioxol-5-yl-methanone (Example 107),
{4-Amino-2-[4-(4-cyclopentyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(2,3-dihydro-benzo[1,4]dioxin-6-yl)-methanone (Example 108),
{4-Amino-2-[4-(4-isopropyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(3-trifluoromethoxy-phenyl)-methanone (Example 109),
{4-Amino-2-[4-(4-isopropyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(3-fluoro-phenyl)-methanone (Example 110),
{4-Amino-2-[4-(4-isopropyl-piperazin-1-yl)-phenylamino)-thiazol-5-yl}-(3-difluoromethoxy-phenyl)-methanone (Example 111),
{4-Amino-2-[4-(4-isopropyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(3-hydroxy-phenyl)-methanone, with acetic acid (Example 112),
{4-Amino-2-[4-(4-isobutyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(3-hydroxy-phenyl)-methanone, with acetic acid (Example 113),
[4-Amino-2-(4-piperazin-1-yl-phenylamino)-thiazol-5-yl]-(3-difluoromethoxy-phenyl)-methanone (Example 114),
{4-Amino-2-[4-(4-cyclopropylmethyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(3-difluoromethoxy-phenyl)-methanone (Example 115),
{4-Amino-2-[4-(4-cyclopropylmethyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(3-methoxy-phenyl)-methanone (Example 116),
{4-Amino-2-[4-(4-cyclopropylmethyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-benzo[1,3]dioxol-5-yl-methanone (Example 117),
{4-Amino-2-[4-(4-cyclopropylmethyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(2,3-dihydro-benzo[1,4]dioxin-6-yl)-methanone (Example 118),
{4-Amino-2-[4-(4-cyclopropylmethyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(3-fluoro-4-hydroxy-phenyl)-methanone (Example 119),
{4-Amino-2-[4-(4-methyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(3-difluoromethoxy-phenyl)-methanone (Example 120),
{4-Amino-2-[4-(4-cyclopropylmethyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(3-fluoro-phenyl)-methanone (Example 121),
{4-Amino-2-[4-(4-cyclopropylmethyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(3-fluoro-4-methoxy-phenyl)-methanone (Example 122),
{4-Amino-2-[4-(4-methyl-piperazin-1-yl)-phenylamino]-thiazol-5-yl}-(3-hydroxy-phenyl)-methanone (Example 123), and
3-{4-Amino-2-[4-(4-methyl-piperazin-1-yl)-phenylamino]-thiazole-5-carbonyl}-benzonitrile (Example 124).
The compounds disclosed herein and covered by formula I above may exhibit tautomerism or structural isomerism. It is intended that the invention encompasses any tautomeric or structural isomeric form of these compounds, or mixtures of such forms, and is not limited to any one tautomeric or structural isomeric form depicted in the formula above.
The compounds of the present invention can be prepared by any conventional means. Suitable processes for synthesizing these compounds are provided in the examples. Generally, compounds of formula I can be prepared according to one of the below described synthetic routes.
A. Ring Formation
Compounds of the invention can be prepared by the alkylation and cyclization of a number of thiourea derivatives, as shown in Scheme I, using reactions that are known. Among the thiourea derivatives that can be used are nitroamidinothioureas (Binu, R. et al. Org. Prep. Proced. Int. 1998, 30, 93-96); 1-[(arylthiocarbamoyl)amino]-3,5-dimethylpyrazoles (Jenardanan, G. C. et al. Synth. Commun. 1997, 27, 3457-3462); and N-(aminoiminomethyl)-Nxe2x80x2-phenylthioureas (Rajasekharan, K. N. et al. Synthesis 1986, 353-355). 
Another thiourea derivative that can be used for the preparation of compounds of the invention by alkylation and cyclization is N-cyanothiourea (Gewald, K. et al. J. Prakt. Chem. 1967, 97-104). For example, pursuant to Scheme IA below, an N-cyanothiourea of formula 4A can be reacted with a halomethylketone, such as a bromomethylketone of formula 5, at a temperature between around room temperature and around 65xc2x0 C., to give a compound of formula 6. 
Alternatively, the compounds of the invention are also conveniently prepared by reaction of a resin-bound substituted (aminothioxomethyl) carbamimidothioic acid methyl ester of formula 8 with a bromomethyl aryl ketone of formula 5 as shown in Scheme II below. 
The resin-bound thiourea derivative of formula 8 can be made by any conventional procedure known to one skilled in the art of organic synthesis. For example, it can be conveniently prepared by the reaction of a resin-bound thiouronium salt of formula 7 with an isothiocyanate of formula 2 in the presence of a base, such as a tertiary amine (e.g., triethylamine or diisopropylethylamine) in an inert solvent, such as a polar aprotic solvent (e.g., N,N-dimethylformamide). The reaction is conveniently carried out at a temperature around room temperature. The resin-bound thiourea derivative of formula 8 is then converted to the product of formula 6 by treatment with a halomethylketone (for example, a bromomethylketone of formula 5) in a suitable inert solvent such as a polar aprotic solvent (e.g., N,N-dimethylformamide) at a temperature around room temperature.
B. Nucleophilic Aromatic Substitution 
As shown in Scheme III above, compounds of formula 1 where R3 represents nitro, R4 represents NR20R21 (wherein R20 and R21 are independently selected from H and lower alkyl which itself can be substituted by OH, or alternatively, NR20R21 can optionally form a ring having 5-6 atoms, said ring including one or more additional hetero atoms and being optionally substituted by OH and lower alkyl which itself may be substituted by OH) and R5 represents hydrogen (that is to say, compounds of formula 10), can be conveniently prepared by treating a compound of formula 9 , with an amine of formula HNR21R20, in the optional presence of an additional base, such as a tertiary amine (e.g., triethylamine or diisopropylethylamine) in an inert solvent, such as a lower alcohol (e.g., ethanol, isopropanol, n-butanol, or the like) or a polar aprotic solvent (e.g., N,N-dimethylformamide). The reaction is conveniently carried out a temperature between about 70 degrees and about 110 degrees, preferably at about the reflux temperature of the solvent or about 100 degrees, whichever is lower.
C. Removal of Protective Groups 
As shown in Scheme IV, compounds of formula I where R1 represents H (that is, compounds of formula 11) can be prepared by removal of a protective group from compounds of formula 30 where R30 represents a protective group commonly used for the protection of a secondary amine. Many such protective groups are known to those of skill in the art of organic synthesis. For example, several suitable protective groups are enumerated in xe2x80x9cProtective Groups in Organic Synthesisxe2x80x9d (Greene, T. W. and Wuts, P. G. M., 2nd Edition, John Wiley and Sons, N.Y. 1991). Preferred protective groups are those compatible with the reaction conditions used to prepare compounds of the invention. One such protective group is the tert-butoxycarbonyl (t-BOC) group. The tert-butoxy carbonyl group can be conveniently removed by treatment of a compound of formula 30 in which R30 represents 
with an acid to give a compound of formula I in which R1 represents H. Examples of acids that can be used to effect this transformation are well known, and include trifluoroacetic acid, hydrochloric acid, hydrofluoric acid, and aluminum chloride. For example, the t-BOC group may be conveniently removed by treating a compound of formula 30 in which R30 represents 
with trifluoroacetic acid, in an inert solvent, such as a halogenated hydrocarbon (e.g., dichloromethane). The reaction can be carried out at a temperature between about 0 degrees and about room temperature, preferably at about room temperature.
D. Separating a Mixture of Stereoisomers into the Optically Pure Stereoisomers (When Compound of Formula I is Chiral)
The optional separation of isomeric structures of formula I can be carried out according to known methods such as for example resolution or chiral high pressure liquid chromatography (also known as chiral HPLC). Resolution methods are well known, and are summarized in xe2x80x9cEnantiomers, Racemates, and Resolutionsxe2x80x9d (Jacques, J. et al. John Wiley and Sons, NY, 1981). Methods for chiral HPLC are also well known, and are summarized in xe2x80x9cSeparation of Enantiomers by Liquid Chromatographic Methodsxe2x80x9d (Pirkle, W. H. and Finn, J. in xe2x80x9cAsymmetric Synthesisxe2x80x9d, Vol. 1, Morrison, J. D., Ed., Academic Press, Inc., NY 1983, pp. 87-124).
E. Converting a Compound of Formula I that Bears a Basic Nitrogen into a Pharmaceutically Acceptable Acid Addition Salt
The optional conversion of a compound of formula I that bears a basic nitrogen into a pharmaceutically acceptable acid addition salt can be effected by conventional means. For example, the compound can be treated with an inorganic acid such as for example hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, or with an appropriate organic acid such as acetic acid, citric acid, tartaric acid, methanesulfonic acid, p-toluenesulfonic acid, or the like.
F. Converting a Compound of Formula I that Bears a Carboxylic Acid Group into a Pharmaceutically Acceptable Alkali Metal Salt
The optional conversion of a compound of formula I that bears a carboxylic acid group into a pharmaceutically acceptable alkali metal salt can be effected by conventional means. For example, the compound can be treated with an inorganic base such as lithium hydroxide, sodium hydroxide, potassium hydroxide, or the like.
G. Converting a Compound of Formula I that Bears a Carboxylic Acid Group into a Pharmaceutically Acceptable Ester
The optional conversion of a compound of formula I that bears a carboxylic acid group into a pharmaceutically acceptable ester can be effected by conventional means. The conditions for the formation of the ester will depend on the stability of the other functional groups in the molecule to the reaction conditions. If the other moieties in the molecule are stable to acidic conditions, the ester may be conveniently prepared by heating in a solution of a mineral acid (e.g., sulfuric acid) in an alcohol. Other methods of preparing the ester, which may be convenient if the molecule is not stable to acidic conditions include treating the compound with an alcohol in the presence of a coupling agent and in the optional presence of additional agents that may accelerate the reaction. Many such coupling agents are known to one skilled in the art of organic chemistry. Two examples are dicyclohexylcarbodiimide and triphenylphosphine/diethyl azodicarboxylate. In the case where dicyclohexylcarbodiimide is used as the coupling agent, the reaction is conveniently carried out by treating the acid with the alcohol, dicyclohexylcarbodiimide, and the optional presence of a catalytic amount (0-10 mole %) of N,N-dimethylaminopyridine, in an inert solvent such as a halogenated hydrocarbon (e.g., dichloromethane) at a temperature between about 0 degrees and about room temperature, preferably at about room temperature. In the case where triphenylphosphine/diethyl azodicarboxylate is used as the coupling agent, the reaction is conveniently carried out by treating the acid with the alcohol, triphenylphosphine and diethyl azodicarboxylate, in an inert solvent such as an ether (e.g., tetrahydrofuran) or an aromatic hydrocarbon (e.g., benzene) at a temperature between about 0 degrees and about room temperature, preferably at about 0 degrees.
Turning to the intermediates, isothiocyanate intermediates of formula 2 used to make compounds of the invention can be made by any conventional means. For example, they may be made by the route shown in Scheme V below. 
The nitro group in a compound of formula 12 can be reduced to give an aniline of formula 13 using a number of methods familiar to one skilled in the art. These methods include (1) treatment of the nitro compound of formula 12 with iron/acetic acid, with tin(II) chloride/hydrochloric acid, or with zinc and ammonium chloride; and (2) hydrogenation in the presence of a noble metal catalyst such as palladium-on-carbon.
The isothiocyanates of formula 2 may be made from anilines of formula 13 using any one of a number of reagents known to those skilled in organic synthesis to be useful for the transformation of an aniline of formula 13 into an isothiocyanate of formula 2. Among these reagents are carbon disulfide, thiophosgene, 1,1xe2x80x2-thiocarbonylbis(2-pyridone), and thiocarbonyl diimidazole. The reaction can be carried out by treating an aniline of formula 13 with thiocarbonyl diimidazole in a suitable inert solvent such as a polar aprotic solvent (e.g., N,N-dimethylformamide) at a temperature between about xe2x88x9220 degrees and about 0 degrees, preferably at about xe2x88x9215 degrees.
Nitro compounds of formula 12 can be made by a variety of methods that are known in the field of organic synthesis. For example, they may be made by the nucleophilic substitution of a nitrobenzene derivative that bears a leaving group at the position para to the nitro group in accordance with Scheme VI below: 
The nucleophilic substitution reaction between an amine of formula 15 and a nitrobenzene of formula 14 (wherein X is a leaving group) to give the substituted product of formula 12 can be conveniently carried out by heating these materials together at a temperature between about 50 and about 100 degrees, preferably at about 80 degrees, in the optional presence of an inert solvent such as acetonitrile (Scheme VI). Suitable leaving groups of formula X include chloride and fluoride. By way of example and not as a limitation, the following compounds of formula 14 are available commercially from the noted vendors:
Alternatively, nitro compounds of formula 12 may be synthesized according to Scheme VII below. 
The alkylation of compounds of formula 16 to give compounds of formula 12, in which R1 represents an alkyl group can be achieved by treating the compound with an alkylating agent of formula 17, in which X represents one of a number of leaving groups well known to those with knowledge of organic synthesis, such as a halide (e.g., chloride, bromide, iodide) or a sulfonate (e.g., mesylate, tosylate, triflate), or the like, in an inert solvent, such as acetonitrile, a lower alkyl ketone (e.g., acetone or 2-butanone), a polar aprotic solvent (e.g., N,N-dimethylformamide), or an aromatic hydrocarbon (e.g., benzene or toluene), in the presence of a base, such as sodium carbonate or potassium carbonate, and in the optional presence of a catalyst such as potassium iodide. Except where the leaving group is triflate, the reaction can be conveniently carried out at a temperature between about 50 degrees and about 110 degrees, preferably at about 80 degrees. Where the leaving group is triflate, the reaction is conveniently carried out at a temperature between about 0 degrees and room temperature, preferably at about room temperature.
Compounds of formula 12 where R1 represents an acyl group may be prepared by acylation of compounds of formula 16. The reaction can be effected using known methods. For example, the compound of formula 16 can be treated with a carboxylic acid of formula 17, in which X represents OH, in the presence of a coupling agent, many examples of which are well known per se in peptide chemistry, and in the optional presence of a substance that increases the rate of the reaction, such as 1-hydroxybenzotriazole or 1-hydroxy-7-azabenzotriazole; or by reaction of the compound of formula 16 with a reactive derivative of carboxylic acids such as the corresponding acid halides (for example, the acid chloride), acid anhydride, mixed anhydride, activated ester, etc. The reaction is conveniently carried out by treating the compound of formula 16 with an acid chloride in the presence of a base such as pyridine, or a tertiary amine (e.g., diisopropylethylamine) or an inorganic base such as sodium or potassium carbonate, in an inert solvent such as a halogenated hydrocarbon (e.g., dichloromethane) at a temperature between about 0 degrees and about room temperature, preferably at about room temperature.
Compounds of formula 12 where R1 represents an alkoxycarbonyl group may be prepared by the alkoxycarbonylation of compounds of formula 16 to give compounds of formula 12, in which R1 represents an alkoxycarbonyl group. This synthesis can be effected using reactions that are well known in the fields of organic chemistry and peptide chemistry. Conditions for many of these reactions are given in xe2x80x9cProtective Groups in Organic Synthesisxe2x80x9d (Greene, T. W. and Wuts, P. G. M., 2nd Edition, John Wiley and Sons, N.Y. 1991). In the case of the preferred alkoxycarbonyl protective group, namely the tert-butoxycarbonyl (t-BOC) group, the protective group can be introduced by reacting the amine of formula 16 with di-tert-butyl dicarbonate in an inert solvent such as a mixture of water and an ether such as dioxane, or in a halogenated solvent (such as dichloromethane), or in acetonitrile, in the optional presence of a base or of a catalyst, such as N,N-dimethylamino-pyridine. As an alternative to di-tert-butyl dicarbonate, the following reagents could also be used: 2-(tert-butoxycarbonyloximino)-2-phenylacetonitrile, or tert-butyl azidoformate.
Compounds of formula 12 where R1 represents a sulfonyl group may be prepared by the sulfonylation of compounds of formula 16 to give compounds of formula 12, in which R1 represents a sulfonyl group. This synthesis can be effected using reactions that are well known in the field of organic chemistry. For example, compounds of formula 12 in which R1 represents a sulfonyl group can be prepared by reaction of compounds of formula 16 with a sulfonyl chloride in the presence of an appropriate base for example pyridine that can also be used as solvent. The reaction may also be performed by using a tertiary amine as the base, in the presence of an inert solvent such as tetrahydrofuran or dichloro-methane; or in aqueous solution using an alkali metal hydroxide such as sodium hydroxide as the base. The reaction is conveniently carried out at a temperature of between about room temperature and about 80 degrees, preferably at about room temperature.
Sample compounds of formula 16 may be obtained as indicated below.
Bromomethylketone intermediates 5 used to make compounds of the invention are available commercially or can be made using one of a number of methods known to those skilled in the art of organic synthesis, for example: Friedel-Crafts reactions of an arene with bromoacetyl bromide or bromoacetyl chloride; oxidation of a 2-bromo-1-phenethyl alcohol; reaction of a diazomethyl ketone with HBr; reduction of a dibromomethyl ketone (see Scheme VIII) below; or reaction of a methyl ketone with a brominating agent (see Scheme IX) such as bromine, copper(II) bromide, tetrabutylammonium tribromide, or 5,5-dibromo-barbituric acid.
According to the method of Diwu et al. (Tetrahedron Lett. 1998, 39, 4987-4990), methyl ketones of formula 19 can be converted into the corresponding dibromomethyl ketones of formula 20 by treatment with bromine in neat sulfuric acid. The dibromomethyl ketones of formula 20 can then be converted into the desired bromomethyl ketones of formula 5 by reduction with diethylphosphite. 
Bromomethyl ketones of formula 5 can also be prepared directly from methyl ketones of formula 19 using a variety of reagents well known to those of ordinary skill in the art of organic synthesis, such as those mentioned above. For example, the reaction may be conveniently carried out by treating the methyl ketone of formula 19 with bromine in a suitable inert solvent such as a halogenated hydrocarbon (e.g., carbon tetrachloride) in the optional presence of other agents that facilitate the reaction, such as a Bronsted or Lewis acid catalyst (e.g., aluminum chloride or acetic acid). The optimal reaction temperature depends on whether or not a catalyst is used. In the case where aluminum chloride is used, the reaction is conveniently carried out at about 0 degrees. In the cases where acetic acid is added, or where no catalyst is used, the reaction is conveniently carried out at a temperature between about room temperature and about 80 degrees, preferably at about room temperature. Alternatively, a methyl ketone of formula 19 may be converted to a bromomethylketone of formula 5 by treatment with copper(II) bromide in a suitable unreactive solvent such as ethyl acetate, preferably at the reflux temperature. 
In an alternative embodiment, the present invention is directed to pharmaceutical compositions comprising at least one compound of formula I, or a pharmaceutically acceptable salt or ester thereof.
These pharmaceutical compositions can be administered orally, for example in the form of tablets, coated tablets, dragees, hard or soft gelatin capsules, solutions, emulsions or suspensions. They can also be administered rectally, for example, in the form of suppositories, or parenterally, for example, in the form of injection solutions.
The pharmaceutical compositions of the present invention comprising compounds of formula I, and/or the salts or esters thereof, may be manufactured in a manner that is known in the art, e.g. by means of conventional mixing, encapsulating, dissolving, granulating, emulsifying, entrapping, dragee-making, or lyophilizing processes. These pharmaceutical preparations can be formulated with therapeutically inert, inorganic or organic carriers. Lactose, corn starch or derivatives thereof, talc, steric acid or its salts can be used as such carriers for tablets, coated tablets, dragees and hard gelatin capsules. Suitable carriers for soft gelatin capsules include vegetable oils, waxes and fats. Depending on the nature of the active substance, no carriers are generally required in the case of soft gelatin capsules. Suitable carriers for the manufacture of solutions and syrups are water, polyols, saccharose, invert sugar and glucose. Suitable carriers for injection are water, alcohols, polyols, glycerine, vegetable oils, phospholipids and surfactants. Suitable carriers for suppositories are natural or hardened oils, waxes, fats and semi-liquid polyols.
The pharmaceutical preparations can also contain preserving agents, solubilizing agents, stabilizing agents, wetting agents, emulsifying agents, sweetening agents, coloring agents, flavoring agents, salts for varying the osmotic pressure, buffers, coating agents or antioxidants. They can also contain other therapeutically valuable substances, including additional active ingredients other than those of formula I.
As mentioned above, the compounds of the present invention, including the compounds of formula I, are useful in the treatment or control of cell proliferative disorders, in particular oncological disorders. These compounds and formulations containing said compounds are particularly useful in the treatment or control of solid tumors, such as, for example, breast, colon, lung and prostate tumors.
A therapeutically effective amount of a compound in accordance with this invention means an amount of compound that is effective to prevent, alleviate or ameliorate symptoms of disease or prolong the survival of the subject being treated. Determination of a therapeutically effective amount is within the skill in the art.
The therapeutically effective amount or dosage of a compound according to this invention can vary within wide limits and may be determined in a manner known in the art. Such dosage will be adjusted to the individual requirements in each particular case including the specific compound(s) being administered, the route of administration, the condition being treated, as well as the patient being treated. In general, in the case of oral or parenteral administration to adult humans weighing approximately 70 Kg, a daily dosage of about 10 mg to about 10,000 mg, preferably from about 200 mg to about 1,000 mg, should be appropriate, although the upper limit may be exceeded when indicated. The daily dosage can be administered as a single dose or in divided doses, or for parenteral administration, it may be given as continuous infusion.
In another embodiment, the present invention is also directed to novel intermediates useful in the preparation of compounds of formula I. These novel intermediates include the following compounds:
1-(2-Fluoro-4-isothiocyanatophenyl)-4-methylpiperazine (Example 2C),
1-(1-Methylethyl)-4-(4-nitrophenylpiperazine) (Example 3A),
4-[4-(1-Methylethyl)-1-piperazinyl]benzenamine (Example 3B),
1-(4-Isothiocyanatophenyl)-4-(1-methylethyl)piperazine (Example 3C),
4-(2-Hydroxyethyl)-1-(4-isothiocyanatophenyl)piperazine (Example 5B),
1-(4-Isothiocyanatophenyl)-4-(2-methoxy-ethyl)piperazine (Example 14B),
1-(4-Isothiocyanatophenyl)-4-(1-methylpropyl)piperazine (Example 14C),
4-Cyclopentyl-1-(4-isothiocyanatophenyl)piperazine (Example 14D),
1-(4-Isothiocyanatophenyl)-4-(2-methylpropyl)piperazine (Example 14E),
4-(3-Hydroxypropyl)-1-(4-isothiocyanatophenyl)piperazine (Example 14F),
2-Bromo-1-(3,4,5-trifluoro-phenyl)ethanone (Example 14H),
2-Bromo-1-(4-fluoro-3-methoxy-phenyl)ethanone (Example 14I),
2-Bromo-1-(4-fluoro-3-methoxy-phenyl)ethanone (Example 14K),
2-Bromo-1-(3-difluoromethoxy-phenyl)ethanone (Example 14L),
[4-amino-2-[[4-(4-methyl-1-piperazinyl)phenyl]amino]-5-thiazolyl](4-chloro-3-nitrophenyl)methanone (Example 15),
Carbamimidothioic acid, [[4-(4-methyl-1-piperazinyl)phenylamino]thioxomethyl], polymer bound (Example 18),
Carbamimidothioic acid, [[3-fluoro-4-(4-methyl-1-piperazinyl)phenylamino]thioxomethyl], polymer bound (Example 19),
Carbamimidothioic acid, [[4-[4-(1-methylethyl)-1-piperazinyl]phenylamino]thioxomethyl], polymer bound (Example 20),
Carbamimidothioic acid, [[4-(4-acetyl-1-piperazinyl)phenylamino]thioxomethyl], polymer bound (Example 21),
Carbamimidothioic acid, [[4-[4-(2-hydroxyethyl)-1-piperazinyl]phenylamino]thioxomethyl], polymer bound (Example 22),
Carbamimidothioic acid, [[4-[4-[(1,1-dimethylethoxy)carbonyl]-1-piperazinyl]phenylamino]thioxomethyl], polymer bound (Example 23A),
Carbamimidothioic acid, [[4-[4-(2-methoxyethyl)-1-piperazinyl]phenylamino]thioxomethyl], polymer bound (Example 23B),
Carbamimidothioic acid, [[4-[4-(1-methylpropyl)-1-piperazinyl]phenylamino]thioxomethyl], polymer bound (Example 23C),
Carbamimidothioic acid, [[4-(4-cyclopentyl-1-piperazinyl)phenylamino]thioxomethyl], polymer bound (Example 23D),
Carbamimidothioic acid, [[4-[4-(2-methylpropyl)-1-piperazinyl]phenylamino]thioxomethyl], polymer bound (Example 23E),
Carbamimidothioic acid, [[4-[4-(3-hydroxypropyl)-1-piperazinyl]phenylamino]thioxomethyl], polymer bound (Example 23F),
4-[4-[[4-Amino-5-(3-fluorobenzoyl)-2-thiazolyi]amino]phenyl]-1-piperazinecarboxylic acid, 1,1-dimethylethyl ester (Example 54A),
4-[4-[[4-Amino-5-[4-(1-pyrrolidinyl)benzoyl]-2-thiazolyl]amino]phenyl]-1-piperazinecarboxylic acid, 1,1-dimethylethyl ester (Example 55A),
4-[4-[[4-Amino-5-(3-fluoro-4-methoxybenzoyl)-2-thiazolyl]amino]phenyl]-1-piperazinecarboxylic acid, 1,1-dimethylethyl ester (Example 56A).